Azides, also

Organoboranes react with a mixture of aqueous NH3 and NaOCl to produce primary amines. It is likely that the actual reagent is chloramine NH2CI. Chloramine itself,hydroxylamine-O-sulfonic acid in diglyme, and trimethyl-silyl azide " also give the reaction. Since the boranes can be prepared by the hydroboration of alkenes (15-16), this is an indirect method for the addition of NH3 to a double bond with anti-Markovnikov orientation. Secondary amines can be prepared by the treatment of alkyl- or aryldichloroboranes or dialkylchlorobor-anes with alkyl or aryl azides. 

Aryl azides also give ring expansion on heating, for example,... 

Diphenylphosphoryl azide also gives good conversion of primary alkyl and secondary benzylic alcohols to azides in the presence of the strong organic base diazabicyc-loundecane (DBU). These reactions proceed by O-phosphorylation followed by Sw2 displacement.78... 

See Methyl azide, also 4-Chlorophenylisocyanate, also Nitrous acid A semicar-bazone, etc. 

In general, acyl azides are too unstable to survive at the temperatures required for addition to acetylenes, although benzoyl azide adds readily to ynamines in toluene. Ethoxycarbonyl azide also gives triazoles in good yield with ynamines. The azide adds to propargylic alcohols in boiling ethanol, and to acetylene at 100° under pressure. Addition to phenylacetylene and to electron-deficient acetylenes has been carried out at 130°. Oxazoles are also formed at this temperature by competing thermal decomposition of the azide, and addition of ethoxycarbonylnitrene to the acetylenes. The triazole obtained from phenylacetylene is 2-ethoxycarbonyl-4-phenyltriazole the two 1-ethoxycarbonyltriazoles can be isolated if the addition is carried out at 50° over several weeks. Since the IH- to -triazole isomerization takes place readily in these systems, a IH-structure cannot be assumed for a triazole formed by addition of these azides. 

Sodium azide also adds to olefins of this t3rpe to give w-triazoles in fairly good yields. A mechanism involving nucleophilic displacement of the substituent X by azide, followed by cyclization of the vinyl azide in the presence of azide ions, has been suggested. An alternative mechanism involves conjugate addition of azide to the double bond, cyclization of the resulting anion, and aromatization. 

Diethyldiphenylcyclopentadienone reacts with 3,5-dinitrophenyl azide on heating to give a pyrid-2-one in a similar reaction with phenyl azide, also suggested to proceed via the nitrene, a bridged intermediate (684) is formed (77TL2463). A different adduct (685) was isolated from the reaction between phthalimidonitrene and tetracyclone when treated with... 

Spontaneous explosions of lead azide also take place during crystallization from saturated solution in ammonium acetate. A detailed study of this phenomenon has been made by Taylor and A. T. Thomas [105]. When the concentration of the solutions and the temperature and conditions of cooling were carefully controlled, they were able to predict the time at which spontaneous explosions occur. E.g. ... 

Mercuric azide, Hg(N3)2, occurs in two allotropic modifications a (orthorhombic) and P (monoclinic), like lead azide (Miles [75] Garner and Gomm [37]). The latter is obtained like /Mead azide, by slow diffusion of the solutions. During crystallization spontaneous explosion may occur. Mercuric azide also explodes during crystallization from a hot, aqueous solution. 

LEAD AZIDE PLANT, ANALYTICAL PROCEDURES. The lead azide plant of the Kankakee Ordnance Works (KOW), Joliet, Illinois, operated by the US Rubber Co manufd dextrinated crystalline LA from Na azide and Pb nitrate in presence of dextrin. Na azide also was manufd at KOW the analytical procedures are described under Sodium Azide, Analytical Procedures... 

The density, refractive index and mol refraction of crystn K azide also have been reported (Ref 27). According to Sax (Ref 49) its toxicity is similar to that... 

Sulfonyl azides react with pyridine to give pyridine 1-sulfonylimides (e.g. 367). However, the analogous reaction with 2,4,6-trimethylpyridine gives some 3-(phenylsulfonylamino) derivative together with the 1-sulfonylimide. Nitrenes derived from photolysis of acyl azides also add to the nitrogen atom to form the corresponding pyridine A-imines (74AHC(17)220). 

Whereas aryl, acyl, and sulfonyl azides decompose in the presence of aluminum trichloride in benzene solution only with evolution of N , alkyl azides also split oif significant amounts of N,-.1 -18 At 50° alkylbenzenes and azomethines are obtained. In order to explain these results, Kreher and Jager suggested that two intermediate complexes may be formed (Scheme IV). According to Goubeau, Allenstein, and... 

Irradiation of acyl azides also has proved useful in organic chemical synthesis. Thus irradiation of Formula 466 gives Formula 467 (25%), the... 

Triazolines obtained by the addition of aryl azides to enamines are generally isolable and a considerable number of triazoline compounds have been prepared in this way (Scheme 45.)208,209 Although usually nitrophenyl azide is used, because electron-withdrawing groups on the azide facilitate addition,28,42 diethylaminophenyl azide also works satisfactorily (Scheme 46).209... 

Reaction of vinyl phosphonium salts with sodium azide also yields triazoles via triazoline intermediates by elimination of triphenylphosphine (Scheme 130).418... 

Irradiation of vinyl azides also produces 1-azirines. In some instances it may be the method of choice since the reaction can be carried out at low temperature and little polymerization of the azirines occurs. 

Nitrotriazoles (74) have been prepared by reaction of l-morpholino-2-nitroethylenes with aryl azides. Tosyl azide also reacts with the nitroenamine, to give the N-unsubstituted triazoles (75) (Scheme 16). In all these reactions, the yields are good (55-75%) when R = H, but much lower (10-30%) when R = Me or Ph.38-65 66... 

The thermal decomposition of fluorine azide also yields N2F2. 

Tetrafluorohydrazine is converted to CINF2 by chlorine under UV irradiation. Reaction of flnorine with chlorine azide also yields chlorodifluoramine. 

---